A map of Fedora packages and dependencies

[seth vidal]

On Tue, 2005-06-21 at 15:40 +0200, Tarjei Knapstad wrote:
> [Disclaimer: This is probably going to end up as a blurb about
> dependencies - bear with me :)]
> 
> Firstly, I was just perusing through the FC4 package description list
> and was reminded of something I've thought of many times:
> 
> Would it be possible to map out the package dependencies in Fedora by
> doing rpm queries and forming a directed graph of the results? (by using
> graphviz or something like that)
> 
> I think such a package dependency map would be quite useful to get an
> overview of the distribution, both for developers and users. "End nodes"
> in the graph could help identify candidates that could be moved to
> extras for instance (you might even tag vertices with the package size).
> >From the users perspective it would get a lot easier to get an overview
> of the impact of removing a package, or if you want to rebuild a
> homebrew package for some reason ("I'd really like to just rebuild this
> package myself to the bleeding edge, but what else would it impact and
> maybe even break, if anything?").
> 
> Secondly I was thinking of a "DependencyLint" kind of tool - a small
> Python script maybe that would go through every installed RPM on a
> system and check if the requirements in the .spec files are correct
> and/or sufficient. Here I'm not quite sure about what the rules are for
> Fedora however - should absolutely everything that's needed to build a
> package be in BuildRequires:? Should every package that has C code
> require glibc? Or is it a goal to be as lax as possible to prevent
> (hopefully) unnecessary build problems?
> 
> In any case I was thinking of maybe using a combination of RPM querying
> and ldd (and possibly other tools). An example (from a FC1 box):
> 
> 1. Get a list of all the RPM's on the system.
> 
> 2. For each package, list the files and grep the bin/ and lib/ stuff.
> For instance 'rpm -ql mutt|grep bin' lists /usr/bin/mutt as one of it's
> files.
> 
> 3. Check which dynamic libraries these binaries and libraries depend on
> using 'ldd'. 'ldd /usr/bin/mutt' lists /usr/lib/libz.so.1 among others.
> 
> 4. For each of these, check which package provides them. 
> 'rpm -q --whatprovides /usr/lib/libz.so.1' returns 'zlib-1.2.0.7-2'
> 
> 5. Finally check that the original package depends on zlib. (This step
> I'm not sure what's the best way to query.) 'rpm -q --requires mutt'
> does not list zlib and 'rpm -e --test zlib' does not list mutt so we've
> actually found a missing dependency here.
> 
> These are just my first thoughts to maybe encourage some discussion. I'm
> sure this could be done in a better way and could probably also be
> expanded to do other stuff (I'm not very RPM-savvy). If you run a live
> testinstall of rawhide for instance such a tool could be run
> automatically after each update to detect any packaging problems wrt.
> dependencies.
> 

1. Do an everything install of core.
2. install yum-utils
3. run package-cleanup --leaves

that'll tell you all the specific leaf nodes.

-sv